Synthetic line is constructed using man-made materials, and is considerably different than natural fiber line. Nylon, dacron, polyethylene and polypropylene are the main types of synthetic fiber line used aboard boats.
Nylon is the most commonly used synthetic line because of its great strength, elasticity and resistance to weather. It is constructed in many ways, making it a versatile choice aboard a boat. Polypropylene line is also widely used because of its strength and ability to float.
Pros of synthetic line: very strong, has excellent resistance to rot, mildew and deterioration, and it is extremely resistant to harmful sunlight U.V. rays and weathering. Another pro of synthetic line is its elasticity in applications where that is an important factor.
Cons of synthetic line: slips much easier than natural line so it is not ideal for knots and for use with deck fittings, its elasticity can be dangerous if it parts during a load bearing operation such as towing, and it is susceptible to chafing from rough surfaces.
